Warming device



Janfl7, 1967 w. LAWSON, JR 3,299,253

, I 1 WARMING DEVICE Filed Oct. 50, 196s Y 2 Sheets-$heet 1 k 5 I INVENTOR. Z MZZ/4/I/ H mw/sa/u J2 BY ywgx Jan. 17, 1967 w. H. LAWSON, JR

' WARMING DEVICE 2 Sheets-Sheet 2 Filed Oct. 50, 1965 ii b United States Patent C) 3,299,253 WARMING DEVICE William H. Lawson, Jr., Northridge, Calif., assignor to The Sierracin Corporation, Burbank, Calif, a corporation of California Filed Oct. 30, 1963, Ser. No. 320,019 4 Claims. (Cl. 219-385) This invention relates to a warming device and more particularly relates to a device for supplying heat to a human body or a part thereof without interfering with the unrestricted visual observation thereof.

Many situations arise, particularly in hospitals, Where a patients entire body, or a part thereof, must be kept warm but in which it is desired not to use blankets or similar coverings. For example, it has been found that the ambient air around a newborn infant should be kept constant during at least the first few hours of life to help him maintain proper body heat. Blankets are presently in common use for this purpose but they have several substantial disadvantages. The infant instinctively fights blankets which are binding. The blankets must be removed when the infant is to be cleaned and examined, thus causing sudden variations in temperature as well as tying up the time of the attending physician or nurse. These blankets, of course, also make it impossible to keep the infant under continual visual observation.

Another instance where it is desired to provide a constant temperature with unimpaired vision is in the treatment of premature infants. Presently, the standard warming device in use is an incubator which forms a complete enclosure kept warm by the flow of warm air therethrough. The top of one incubator is also provided with an incandescent source of infrared heat energy which is radiated downward on the infant to supplement the prime heat source. This radiant heat source severely interferes with the complete visual observation of the incubators occupant. Handling of the infant in the incubator is usually awkward and unwieldy as well.

Another example of the desirability of maintaining a constant temperature while permitting complete visual observation and free access is in the case of a severe burn or wound on any part of a patients body. A severely burned leg, for example, should be kept free of any coverings so as to permit free access of air, and yet should be kept warm. In this case also it is desirable that the wound or burn be observable without the need for removing any coverings while continuing treatment. Another example is the case of a patient who is allergic to blankets or who has a skin rash that would be irritated by contact with blankets.

It is therefore an object of the present invention to provide a warming device that maintains a constant ambient temperature about a subject while permitting free access to the subject and unimpaired visual observation of the subject.

It is also an object of the present invention to provide such a device having a transparent electrical conductive film or resistive wires laminated into a transparent cover or shield.

It is another object of the present invention to provide such a device wherein means are provided for maintaining the ambient temperature constant by controlling the current in the film or wires.

3,299,253 Patented Jan. 17, 1967 These and other objects and advantages of the present invention will become more apparent upon reference to the accompanying description and drawings in which:

FIGURE 1 is a plan view of a warming device constructed according to the present invention before it is provided with its final contour;

FIGURE 2 is a view, partly broken away and in section, showing a portion of the warming device of FIGURE '1;

FIGURE 3 is a perspective view of the warming device in position on a typical hospital bassinet;

FIGURE 4 is a sectional view taken along lines 4-4 of FIGURE 2;

FIGURE 5 is a view, partly in section, taken along lines 55 of FIGURE 1; and

FIGURE 6 is a sectional detail showing one manner in which a temperature controller may be mounted.

According to the present invention, these objects are realized by providing a device that produces a constant, even heat uniformly radiated over a patients body, or a part thereof, but permits free access to the patient and does not in any way impair the vision of the attending physician or nurse. The device is thus ideal for use in the treatment of newborn infants and the other classes of patients discussed above. The present invention utilizes a transparent, heat radiating shield that can be positioned a short distance from the patient and shaped so as to provide suitable means of access to the patient. The invention also provides sensing and regulating means to assure that the ambient temperature in the space under the shield is kept constant at a predetermined level. Thus, for example, a newborn infant can be placed under the shield of the present invention shortly after birth and be kept in a constant temperature region while being treated, examined or cleaned, the shield in no way impairing the vision of the attendant.

Referring now to FIGURE 1, there is shown a warming device, generally indicated at 10, which includes a transparent shield 11 having embedded therein a transparent film 12 of conductive material. This film 12 covers the major portion of the area of the shield 11 and, as shown, is deposited in a generally rectangular pattern. Means 13 and 14 are provided at either end of the film 12 of conductive material to supply electrical current thereto, and a pair of temperature sensing elements 15 and 16 are embedded in the shield 11. Means 13 and 14 and the temperature sensors 15 and 16 are all connected to a temperature controller 17 which acts in response to the signals received from the temperature sensors 15 and 16 to control the current in the film 12.

The construction of the device shown in FIGURE 1 can be more readily understood by reference to FIGURES 2, 4, 5 and 6. As can be seen from FIGURES 2 and 4, the shield 11 includes a layer 20 of any suitable transparent material such as a polyester plastic. Other suitable transparent materials such as glass could also be used. A thin transparent film 21 of a conductive material is deposited on the layer 20. This film may be of any suitable conventional material and may be applied in any conventional manner, for example by thermally evaporating by vacuum techniques a metal such as gold, silver, copper, iron or nickel onto the layer 20, or by the application of any semiconductive materials such as st-annic oxide in any conventional manner.

After the conductive film has been deposited on the sheet 20, a bus bar 22 is formed at each end of the pattern.

This bus bar, for example, may be formed by painting a silver strip along the entire end of the pattern. A braided conductor 23 is then placed on top of the bus bar 22 and in electrical contact therewith. The braided conductor 23 is used as the lead connecting the bus bar 22 with the controller 17. A soft interlayer 2.4 of a transparent plastic such as polyvinyl butyral is then placed over the layer 20, film 21, bus bar 22 and braid 23. This inte-rlayer 24 is formed of one or more thin sheets of plastic, one of which is provided with cutouts into which fit the sensors 15 and 16. An internal separator 25 is provided between the vinyl layers to prevent their stripping as is well known in the art.

A second layer 26 of transparent material is then positioned over the entire assembly. The configuration of this second layer 26 should normally be the same as that of the bottom layer 20. The combination of the bus bar 22 and braid 23 makes up the means 14 shown in FIG- URE l for supplying current to the conductive film 12. The means 13 is, of course, constructed in the identical manner.

The composite structure thus formed is now subjected to a high temperature and pressure and the various sheets are thereby laminated together. The cover or shield 11 is then bent or formed to the desired shape and trimmed, or it may be left fiat if this configuration is called for. For example, the shield 11 may be shaped to conform to presently existing equipment, such as the bassinet shown generally at 30 in FIGURE 3. The cover can be attached to the bassinet by conventional clamps 31 or hinges or the like. The cover thus formed provides a heat-producing shield over the infant which is transparent to permit continuous visible observation of the infant. Moreover, since the ends of the shield are open, access to the interior of the bassinet is permitted so that the infant may be treated without varying the heat supplied to it.

As can be seen from FIGURES and 6, the controller 17 is mounted on the outer layer 26 of the shield 11 over an aperture 34 formed in this layer. One manner in which the controller may be held in place is by drilling a number of holes through all three layers of the shield 11, inserting a rubber bushing 35 in each hole, and then bolting the back plate 36 of the controller 17 to the shield 11 by means of bolts 37 and nuts 38. The rest of the controller can then be mounted on the back plate 36 by screws 39. Prior to the mounting of the controller 17, holes are drilled in the interface layer 24 to free the ends of the braided conductors 23 and the conductors leading from the sensors 15 and 16 and these conductors may then be connected to the appropriate leads of the controller 17 by conventional power connectors 40.

The controller 17 may be of any conventional type for regulating the flow of current in a circuit in response to the signal output of a temperature sensing unit. One of the sensors 14 and 15 is preferably used to sense the actual temperature in the shield and governs the action of the controller in accordance therewith. The other sensor is preferably used as a limit sensor which disables the controller when the temperature rises above a predetermined maximum and thus serves as a fail-safe device. Other sensors may also be provided at different points, for example in the ambient air at any desired point within the bassinet or at a point on the skin of the infant as shown at 41 in FIGURE 3, the latter providing a means for sensing the skin temperature of the infant and controlling the current flow to maintain the skin temperature at a desired level. The controller may be provided with a suitable switch to connect any of the temperature sensors into the circuit. As will be obvious, it is not necessary that the sensors be actually embedded in the shield; they may be located in any suitable positions to monitor the temperatures to be controlled.

In the construction of the shield, the outer layer 26 is preferably made at least twice as thick as the bottom layer 20. This extra thickness, together with the thick- 4. ness of the interlayer 24, acts as an insulating barrier to the heat energy radiated by the conductive film and thus concentrates the majority of this heat in the enclosure being heated. The radiated heat is evenly distributed over the baby and causes no dehydration as does convection heating.

The embodiment of the invention illustrated and previously described utilizes a transparent conductive film to provide the heat energy. Other equivalent means may be utilized equally well for this purpose. For example, thin resistive wires may be positioned longitudinally between the bus bars 22 and electrically connected thereto. The number and spacing of thesewires are determined by their resistance and the heat energy to be produced. In no event, however, will their total area amount to more than a very small fraction of the total area of the shield and they will therefore not significantly aifect the overall transparency of the shield. Any of the various patterns that will occur to those skilled in the art for the disposition of these wires in the shield may be used without departing from the teachings of the present invention. Such a pattern, together with its associated bus bars and sensors, may be embedded in a single sheet of transparent material if desired.

Although the present invention has been described in connection with warming a bassinet or the like, it should be understood that it is equally useful for warming any enclosure where it is desired to keep the contents thereof under visual observation, to provide a means of access, and to maintain a constant temperature. The present embodiment is therefore to be considered as illustrative and not restrictive, the scope of the invention being defined by the appended claims.

I claim:

1. A device for covering and warming a body without obstructing the visual observation thereof comprising an arcuate transparent shield for positioning over said body, means in said shield for producing radiant heat energy over substantially the entire surface thereof, the arcuate shape of said shield directing said radiant heat energy toward said body, means immediately associated with said body for sensing the temperature of said body, and means responsive to said sensing means for controlling the heat energy produced by said means in said shield whereby the temperature of said body is maintained at a desired level.

2. The device of claim 1 wherein both ends of said shield are open to provide access to said body.

3. A device for covering and warming a body positioned on a support while permitting free access to and unobstructed visual observation of said body comprising an arcuate transparent shield for positioning over said body and having open ends, current conducting means embedded in said shield for producing radiant heat energy over substantially the entire surface thereof, the arcuate shape of said shield directing said radiant heat energy toward said body and said support whereby said body and said support are heated, means connected to said current conducting means for supplying current thereto, means immediately associated with said body for sensing the temperature of said body and producing an output signal in response thereto, and means connected to said current supplying means and to said sensing means and responsive to the output thereof for controlling the current in said current conducting means whereby the temperature of said body is maintained at a desired level.

4. A device for covering and warming a body positioned on a support while permitting free access to and unobstructed visual observation of said body comprising: an

arcuate transparent shield for positioning on said support over said body, said shield having open ends, current conducting means embedded in said shield for producing radiant heat energy over substantially the entire surface thereof, the arcuate shape of said shield directing said radiant heat energy toward said body and said support to heat them whereby all surfaces adjacent said body are at least at the temperature of said body, means connected to said current conducting means for supplying current thereto, means immediately associated with said body for sensing the temperature of said body and producing an output signal in response thereto, and means connected to said current supplying means and to said sensing means and responsive to the output thereof for controlling the current in said current conducting means whereby the temperature of said body is maintained at a desired level.

References Cited by the Examiner UNITED STATES PATENTS 2,269,566 1/1942 Van Daam 219-542 X 2,409,083 10/ 1946 Valverde 128-102 2,513,993 7/ 1950 Burton 219-202 X Mershon 219-203 X Meredith et a1. 219-549 X Peterson 219-303 Packard 219-202 X Scherck 219-385 X Van Sciver 219-415 X Brady 219-522 X Scofield 219-407 X Cook et a1. 219-202 RICHARD M. WOOD, Primary Examiner.

5 C. L. ALBRITTON, Assistant Examiner.

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 299 ,253 January 17 1967 William H. Lawson, Jr.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 2, "2,629,566" should read 2,649,533

Signed and sealed this 9th day of December 1969.

(SEAL) Attest:

Edward M. Fletcher, J r.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR. 

1. A DEVICE FOR COVERING AND WARMING A BODY WITHOUT OBSTRUCTING THE VISUAL OBSERVATION THEREOF COMPRISING AN ARCUATE TRANSPARENT SHIELD FOR POSITIONING OVER SAID BODY, MEANS IN SAID SHIELD FOR PRODUCING RADIANT HEAT ENERGY OVER SUBSTANTIALLY THE ENTIRE SURFACE THEREOF, THE ARCUATE SHAPE OF SAID SHIELD DIRECTING SAID RADIANT HEAT ENERGY TOWARD SAID BODY, MEANS IMMEDIATELY ASSOCIATED WITH SAID BODY FOR SENSING THE TEMPERATURE OF SAID BODY, AND MEANS RESPONSIVE TO SAID SENSING MEANS FOR CONTROLLING THE HEAT ENERGY PRODUCED BY SAID MEANS IN SAID SHIELD 